Document Detail


Sex Differences in Siberian Hamster Ultradian Locomotor Rhythms.
MedLine Citation:
PMID:  23333554     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Sex differences in ultradian activity rhythms (URs) and circadian rhythms (CRs) were assessed in Siberian hamsters kept in long day (LD) or short day (SD) photoperiods for 40 weeks. For both sexes URs of locomotor activity were more prevalent, greater in amplitude and more robust in SDs. The UR period was longer in females than males in both day lengths. The reproductive system underwent regression and body mass declined during the initial 10 weeks of SD treatment, and in both sexes these traits spontaneously reverted to the LD phenotype at or before 40 weeks in SD, reflecting the development of neuroendocrine refractoriness to SD patterns of melatonin secretion. Hamsters of both sexes, however, continued to display SD-like URs at the 40 week time point. CRs were less prevalent and the waveform less robust and lower in amplitude in SDs than LDs; the SD circadian waveform also did not revert to the long-day phenotype after 40 weeks of SD treatment. Short day lengths enhanced ultradian and diminished circadian rhythms in both sexes. Day length controls several UR characteristics via gonadal steroid and melatonin-independent mechanisms. Sex differences in ultradian timing may contribute to sex diphenisms in rhythms of sleep, food intake and exercise.
Authors:
Brian J Prendergast; Tyler J Stevenson; Irving Zucker
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-17
Journal Detail:
Title:  Physiology & behavior     Volume:  -     ISSN:  1873-507X     ISO Abbreviation:  Physiol. Behav.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0151504     Medline TA:  Physiol Behav     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012. Published by Elsevier Inc.
Affiliation:
Department of Psychology, University of Chicago, Chicago, IL 60637 USA; Committee on Neurobiology, University of Chicago, Chicago, IL 60637 USA. Electronic address: prendergast@uchicago.edu.
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